Today, a corporate enterprise network is the communication backbone that securely connects the different offices and divisions of a corporation. This network is typically a wide area network (WAN) that connects (1) users in branch offices and regional campuses, (2) corporate datacenters that host business applications, Intranets and their corresponding data, and (3) the global Internet through corporate firewalls and DMZ (demilitarized zone). Enterprise networks include specialized hardware such as switches, routers and middlebox appliances interconnected by expensive leased lines, such as Frame Relay and MPLS (multiprotocol label switching).
In the last several years, there has been a paradigm shift in the way corporations serve and consume communication services. First, the mobility revolution has allowed users to access services from any place at any time using mobile devices, mostly smart phones. Such users access the business services through public Internet and cellular networks. At the same time, third-party SaaS (Software as a Service) vendors (e.g., Salesforce, Workday, Zendesk) have replaced traditional on-premise applications, while other applications hosted in private datacenters have been relocated to the public clouds. While this traffic is still carried within the enterprise network, a significant portion of it originates and terminates outside the corporate network perimeters and has to cross both the public Internet (once or twice) as well as the corporate network. Recent studies have shown that 40% of corporate networks report that the percentage of backhauled traffic (i.e., of Internet traffic observed in the corporate network) is above 80%. This means that the majority of the corporate traffic is carried over both expensive leased lines and the consumer Internet.
As a consumer-centric service, the Internet itself is a poor medium for business traffic. It lacks the reliability, QoS (quality of service) guarantees and security expected by critical business applications. Moreover, the ever-increasing consumer traffic demands, net-neutrality regulations and the creation of Internet bypasses by major players (e.g., Netflix, Google, public clouds) have lowered the monetary return per traffic unit. These trends have reduced the incentives of service providers to quickly catch up with the consumer demands and offer adequate business services.
Given the growth of public clouds, corporations are migrating more of their compute infrastructure to the public cloud datacenters. Public cloud providers have been at the forefront of compute and networking infrastructure investment. These cloud services have built many datacenters across the world, with Azure, AWS, IBM and Google expanding to 38, 16, 25, and 14 worldwide regions respectively in 2016. Each public cloud provider has interconnected its own datacenters by using expensive high-speed networks that employ dark fiber and undersea cables deployed by submarines.
Today, notwithstanding these changes, corporate network policies often force all corporate traffic to go through their secure WAN gateways. As users become mobile and applications migrate to SaaS and public clouds, corporate WANs become costly detours that slow down all corporate communications. Most corporate WAN's traffic is either sourced from or destined to the Internet. Alternate secure solutions that send this traffic through the Internet are not adequate because of their poor and unreliable performance.